mm/page_alloc: add a missing mm_page_alloc_zone_locked() tracepoint

The trace point *trace_mm_page_alloc_zone_locked()* in __rmqueue() does
not currently cover all branches.  Add the missing tracepoint and check
the page before do that.

[akpm@linux-foundation.org: use IS_ENABLED() to suppress warning]

Link: https://lkml.kernel.org/r/20201228132901.41523-1-carver4lio@163.com
Signed-off-by: Hailong liu <liu.hailong6@zte.com.cn>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index bdbec4c..027f648 100644 (file)
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -2862,20 +2862,20 @@ __rmqueue(struct zone *zone, unsigned int order, int migratetype,
 {
        struct page *page;
 
-#ifdef CONFIG_CMA
-       /*
-        * Balance movable allocations between regular and CMA areas by
-        * allocating from CMA when over half of the zone's free memory
-        * is in the CMA area.
-        */
-       if (alloc_flags & ALLOC_CMA &&
-           zone_page_state(zone, NR_FREE_CMA_PAGES) >
-           zone_page_state(zone, NR_FREE_PAGES) / 2) {
-               page = __rmqueue_cma_fallback(zone, order);
-               if (page)
-                       return page;
+       if (IS_ENABLED(CONFIG_CMA)) {
+               /*
+                * Balance movable allocations between regular and CMA areas by
+                * allocating from CMA when over half of the zone's free memory
+                * is in the CMA area.
+                */
+               if (alloc_flags & ALLOC_CMA &&
+                   zone_page_state(zone, NR_FREE_CMA_PAGES) >
+                   zone_page_state(zone, NR_FREE_PAGES) / 2) {
+                       page = __rmqueue_cma_fallback(zone, order);
+                       if (page)
+                               goto out;
+               }
        }
-#endif
 retry:
        page = __rmqueue_smallest(zone, order, migratetype);
        if (unlikely(!page)) {
@@ -2886,8 +2886,9 @@ retry:
                                                                alloc_flags))
                        goto retry;
        }
-
-       trace_mm_page_alloc_zone_locked(page, order, migratetype);
+out:
+       if (page)
+               trace_mm_page_alloc_zone_locked(page, order, migratetype);
        return page;
 }